After the divorce from vtest, marry it again as a submodule

[nigoroll]

please note:

• for now, the submodule is https://github.com/nigoroll/VTest
  because of additional changes to vtest required
  (PR is stand-alone build without $VARNISH_SRC defined vtest/VTest#3 )

• This will change the procedure to check out the sources:
  (not yet docmented)

  git clone --recursive

  or, if already cloned

  git submodule update --init

• To pull

  git pull --recurse-submodules

[nigoroll]

travis: make[3]: *** No rule to make target `vtest/src/vtc_h2_dectbl.h', needed by `distdir'. Stop.
seems like we need to teach it how to work with submodules

[bsdphk]

Thanks for doing this Nils.

I think my conclusion is that the time is not ripe for this yet.

How we integrate vtest ultimately depends on what the vtest project develops into.

Right now it is sort of a "source-code library" and the manual integration is not a big deal.

If vtest development picks up, that calculus will change and if so, we will make new decisions.

[nigoroll]

VDD: revive this